{"id":1414,"date":"2024-07-24T15:36:48","date_gmt":"2024-07-24T07:36:48","guid":{"rendered":"https:\/\/swordofmorning.com\/?p=1414"},"modified":"2025-10-09T13:54:44","modified_gmt":"2025-10-09T05:54:44","slug":"rv1126-04","status":"publish","type":"post","link":"https:\/\/swordofmorning.com\/index.php\/2024\/07\/24\/rv1126-04\/","title":{"rendered":"RV1126 \u8fdb\u4e00\u6b65\u7684\u9a71\u52a8\u7a0b\u5e8f"},"content":{"rendered":"

  \u5728\u672c\u7ae0\u4e2d\uff0c\u6211\u4eec\u5c06\u7f16\u5199\u4e00\u4e2a\u53ef\u4ee5\u63a5\u53d7\u4e24\u4e2aint<\/code>\u578b\u53c2\u6570\u548c\u4e00\u4e2achar<\/code>\u578b\u53c2\u6570\u7684\u9a71\u52a8\uff0c\u5e76\u6839\u636echar<\/code>\u7684\u7c7b\u578b\u2014\u2014+<\/code>\u6216\u8005-<\/code>\u2014\u2014\u6765\u8ba1\u7b97\u7ed3\u679c\uff0c\u5e76\u6700\u7ec8\u53ef\u4ee5\u901a\u8fc7read<\/code>\u8fd4\u56de\u8fd9\u4e00\u7ed3\u679c\u3002<\/p>\n

\u4e00\u3001\u9a71\u52a8\u7a0b\u5e8f<\/h2>\n
#include <linux\/module.h>\n#include <linux\/fs.h>\n#include <linux\/uaccess.h>\n#include <linux\/init.h>\n#include <linux\/miscdevice.h>\n#include <linux\/types.h>\n\n#define DEVICE_NAME "my_calc"\n\nstatic int result;\n\nstatic ssize_t my_driver_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)\n{\n    char result_str[16];\n    int len;\n\n    if (*ppos > 0)\n        return 0;\n\n    len = snprintf(result_str, sizeof(result_str), "%d\\n", result);\n\n    if (count < len)\n        return -EINVAL;\n\n    if (copy_to_user(buf, result_str, len))\n        return -EFAULT;\n\n    *ppos = len;\n    return len;\n}\n\nstatic ssize_t my_driver_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)\n{\n    uint32_t a, b;\n    uint8_t symbol;\n\n    if (count != sizeof(uint32_t) * 2 + sizeof(uint8_t))\n        return -EINVAL;\n\n    if (copy_from_user(&a, buf, sizeof(uint32_t)))\n        return -EFAULT;\n\n    if (copy_from_user(&b, buf + sizeof(uint32_t), sizeof(uint32_t)))\n        return -EFAULT;\n\n    if (copy_from_user(&symbol, buf + 2 * sizeof(uint32_t), sizeof(uint8_t)))\n        return -EFAULT;\n\n    switch (symbol) {\n        case '+':\n            result = a + b;\n            break;\n        case '-':\n            result = a - b;\n            break;\n        default:\n            return -EINVAL;\n    }\n\n    return count;\n}\n\nstatic const struct file_operations my_driver_fops = {\n    .owner = THIS_MODULE,\n    .read = my_driver_read,\n    .write = my_driver_write,\n};\n\nstatic struct miscdevice my_driver_device = {\n    .minor = MISC_DYNAMIC_MINOR,\n    .name = DEVICE_NAME,\n    .fops = &my_driver_fops,\n};\n\nstatic int __init my_driver_init(void)\n{\n    int ret;\n\n    ret = misc_register(&my_driver_device);\n    if (ret)\n        pr_err("Failed to register misc device\\n");\n\n    return ret;\n}\n\nstatic void __exit my_driver_exit(void)\n{\n    misc_deregister(&my_driver_device);\n}\n\nmodule_init(my_driver_init);\nmodule_exit(my_driver_exit);\n\nMODULE_LICENSE("GPL");\nMODULE_AUTHOR("Author");\nMODULE_DESCRIPTION("A simple calculator driver");<\/code><\/pre>\n
\u4e8c\u3001\u5e94\u7528\u7a0b\u5e8f<\/h2>\n
#include <stdio.h>\n#include <stdlib.h>\n#include <fcntl.h>\n#include <unistd.h>\n#include <cstring>\n\n#define DEVICE_PATH "\/dev\/my_calc"\n\nint main(int argc, char *argv[])\n{\n    int fd;\n    int a, b, result;\n    char symbol;\n    char buffer[16];\n    char write_buffer[9];\n\n    if (argc != 4) {\n        fprintf(stderr, "Usage: %s <a> <b> <symbol>\\n", argv[0]);\n        exit(EXIT_FAILURE);\n    }\n\n    a = atoi(argv[1]);\n    b = atoi(argv[2]);\n\n    symbol = argv[3][0];\n\n    if (symbol != '+' && symbol != '-') {\n        fprintf(stderr, "Invalid symbol. Use '+' or '-'.\\n");\n        exit(EXIT_FAILURE);\n    }\n\n    fd = open(DEVICE_PATH, O_RDWR);\n    if (fd == -1) {\n        perror("Failed to open device");\n        exit(EXIT_FAILURE);\n    }\n\n    \/\/ \u5c06\u6570\u636e\u6253\u5305\u5230 write_buffer \u4e2d\n    memcpy(write_buffer, &a, sizeof(int));\n    memcpy(write_buffer + sizeof(int), &b, sizeof(int));\n    memcpy(write_buffer + 2 * sizeof(int), &symbol, sizeof(char));\n\n    \/\/ \u4e00\u6b21\u6027\u5199\u5165\u6240\u6709\u6570\u636e\n    if (write(fd, write_buffer, sizeof(write_buffer)) != sizeof(write_buffer)) {\n        perror("Failed to write data to device");\n        close(fd);\n        exit(EXIT_FAILURE);\n    }\n\n    if (read(fd, buffer, sizeof(buffer)) == -1) {\n        perror("Failed to read result from device");\n        close(fd);\n        exit(EXIT_FAILURE);\n    }\n\n    result = atoi(buffer);\n\n    printf("%d %c %d = %d\\n", a, symbol, b, result);\n\n    close(fd);\n    return 0;\n}<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
  \u5728\u672c\u7ae0\u4e2d\uff0c\u6211\u4eec\u5c06\u7f16\u5199\u4e00\u4e2a\u53ef\u4ee5\u63a5\u53d7\u4e24\u4e2aint\u578b\u53c2\u6570\u548c\u4e00\u4e2achar\u578b\u53c2\u6570\u7684\u9a71\u52a8\uff0c\u5e76\u6839\u636echar\u7684\u7c7b\u578b\u2014\u2014+\u6216\u8005 …<\/p>","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[46],"tags":[303],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/swordofmorning.com\/index.php\/wp-json\/wp\/v2\/posts\/1414"}],"collection":[{"href":"https:\/\/swordofmorning.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/swordofmorning.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/swordofmorning.com\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/swordofmorning.com\/index.php\/wp-json\/wp\/v2\/comments?post=1414"}],"version-history":[{"count":1,"href":"https:\/\/swordofmorning.com\/index.php\/wp-json\/wp\/v2\/posts\/1414\/revisions"}],"predecessor-version":[{"id":1415,"href":"https:\/\/swordofmorning.com\/index.php\/wp-json\/wp\/v2\/posts\/1414\/revisions\/1415"}],"wp:attachment":[{"href":"https:\/\/swordofmorning.com\/index.php\/wp-json\/wp\/v2\/media?parent=1414"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/swordofmorning.com\/index.php\/wp-json\/wp\/v2\/categories?post=1414"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/swordofmorning.com\/index.php\/wp-json\/wp\/v2\/tags?post=1414"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}